Improvement in furnaces for smelting iron ore



P. KERR. I

Blast Furriace.

No. 32,426. Patented May '28,-1861.

NITED, STATES PATENT FICE.

PATRICK KERR, OF NEW BETHLEHEM, PENNSYLVANIA.

Specification forming part of Letters Patent No. 32,426, dated May '28,1861.

Y0 all whom it may concern.-

Be it known that I, PATRICK KERR, of New Bethlehem, in the county ofOlarion and State of Pennsylvania, have invented and discovered certainnew and useful Improvements in Smelting Iron Ore with Raw BituminousCoal;

and I do hereby declare that the following is a full, clear, and exactdescription of the same, reference being had to the accompanyingdrawing, making a part of this specification.

I only consider it requisite to describe the interior of the furnace.

Ais the stack above the bosh; B, the chamber between the boshes, termedthe hearth C, an openmetallic thimble at the top of the stack; a a, thecap-plate. D D are fines partially opposite the thimble, and D flueplaced below the others; E E, openings for the tuyeres; c, an opening atthe back of the hearth at a slightlyhigher level than others. I) b and 11 are the lines of the bosh which are continued up at a second angle tod. '00 and 2 2, continued to d d, is a second form,while 3 3, continuedin an unbroken line to cl (1, is a third form, which may be called ahearth and no bosh; and these modifications are more specificallydescribed hereinafter.

Theinnerbosh (marked 1 1) is the form-to be employed whensemi-bituminous coal is to be used. The intermediate form (marked 22,8m. is that for ordinary bituminous, and that marked 3 3, &c., for coalin which the bituminous is in excess. There may be other modificationsof form under the controlling law that as the coal becomes morebituminous the elbow or bosh is to be proportionally diminished.

It is well known that in bituminous coal there is a great difference ofquality, arising, chiefly, from the proportion or quantity of bitumentherein. Previousto my discovery of taking advantage of these qualitiesthe employment of these coals in a crude or raw state had been attendedwith difficulties so greatas to prevent there use in successfullysmelting iron ore. By a long continued course of operations andobservations I have traced one of the difficulties to that property ofexpansion or swelling of the bitumen in the coal by which the properworking of the furnace was impeded, thus causing the' charge of coal andore to hang and work unevenly, and the furnace to jump when a very largeamount of stock comes to work at once. I further effect a great savingof fuel by my improvementsat least twenty-five bushels of coal foreachton of metal madeand by the creation ofa more intense heat from theconsumption of the gases (otherwise lost in coking) a greater. amount ofsteam from the boilers employed in the blast is obtained, while thehot-blast itself is increased in temperature. The increase of heat alsothrows off the sulphur into the slag or dissipates it.

The nature of my improvement consists in the discovery of suchmodifications of form to be given to the furnace that each variety ofbituminous coal may have a form of construction to suitits'properties,and thus all descrip tions of raw bituminous coal may be employed forsmelting iron ore. In addition to the advantages above alluded to thequality of the iron is decidedly improved and quantity in-- creased. outof the same amount of stock. The saving of labor in handling the coal incoking is not to be overlooked, and the prevention of jumping, whichsecures the even working of the furnace by the regularity ofsetting,prevents the chilling thereof, which is a very important item.The improvement in the quality of the iron by the-reduction of theamount of fuellessens the consequent quantity of sulphur in the charge,and the increased degree of intensity of heat liquefies the metal, thusallowing of its being more perfectly purified in its passage through thecinder. My introduction of a thimble in connection with the openings forthe flues conveying the escaped gases to the boilers and hot-blastdelivers the stock more in the center of the furnace, keeps it from thewalls, prevents the escape of gas at the tunnel-head, and enables me towork with a lower stack.

The following directions for the inside may serve as a general guide inbuilding one of my furnaces. That shown in the drawing is twelve feetacross the bosh and forty feet high. The inclination of the line of thehearth from 1 to b is two inches to the foot-rise, then from b to e fiveinches inclination. This is for asemibituminous coal. For bituminous,the bosh is to be between the extremes delineated 2, c, and d. Theexterior figure-via, from 3 to d, and which is without an angle-is forcoal in which the bitumen is in excess, The bottom of the smallesthearth is four feet at its base, the next six, and the outside one eightfeet in diameter, with a projection of about three feet beyond thislastcircle, and in width two feet. The dam f two feet high, the sidetuyeres, E E, are five inches, and the back tuyere, 6, seven inchesabove the top of the dam. The nozzles are three inches in diameter,observing that the bottom of the openings and tuyeres should be level.The thimble 0 should be four feet high and of the inner diameter of thestack at the tunnel-headviz., four feet. It is best made of boiler-ironhaving a flange which catches on the cap-plate. About a foot below itstop there are three holes for the admission of atmospheric air andigniting the gas in the thimble when the charge is above the bottomthereof. The openings D D for the flues are three feet high and twentyinches wide, arched at top, so placed that their bottoms will be sevenfeet below the'capplate and rising one foot above the lower edge of thethimble. The second pair of. flue-holes, D (one shown) have theirbottoms about tcn feet below the cap-plate.

In charging the furnace, the quantity of coal should not exceed fifteenbushels.

Having described my improvement, whatI claim as my invention, and desireto secure by Letters Patent, is

The use of bosh and hearth constructed as hereinbefore described and setforth, in which the width or proportion is reduced or enlarged as thequantity of bitumen in the coal employed as fuel is increased ordiminished.

' In testimony whereof Ihave hereunto signed my name before twosubscribing witnesses.

Witnesses:

JOHN F. CLARK, EDM. F. BRoWN.

